diff --git a/jest/preprocessor.js b/jest/preprocessor.js
index 88eb66680..d0c0582be 100644
--- a/jest/preprocessor.js
+++ b/jest/preprocessor.js
@@ -34,11 +34,15 @@ module.exports = {
       ).code;
     }
 
-    return transformer.transform(src, file, {
-      dev: true,
-      inlineRequires: true,
-      platform: '',
-      projectRoot: '',
+    return transformer.transform({
+      filename: file,
+      options: {
+        dev: true,
+        inlineRequires: true,
+        platform: '',
+        projectRoot: '',
+      },
+      src,
     }).code;
   },
 
diff --git a/packager/package.json b/packager/package.json
index e6386cc91..e04a905ad 100644
--- a/packager/package.json
+++ b/packager/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "0.5.1",
+  "version": "0.6.0",
   "name": "react-native-packager",
   "description": "Build native apps with React!",
   "repository": {
diff --git a/packager/src/JSTransformer/worker/__tests__/worker-test.js b/packager/src/JSTransformer/worker/__tests__/worker-test.js
index d3512e43d..262deeac8 100644
--- a/packager/src/JSTransformer/worker/__tests__/worker-test.js
+++ b/packager/src/JSTransformer/worker/__tests__/worker-test.js
@@ -26,7 +26,7 @@ describe('code transformation worker:', () => {
     extractDependencies =
       require('../extract-dependencies').mockReturnValue({});
     transformer = {
-      transform: jest.fn((src, filename, options) => ({
+      transform: jest.fn(({filename, options, src}) => ({
         code: src,
         map: {},
       })),
@@ -38,22 +38,22 @@ describe('code transformation worker:', () => {
     const sourceCode = 'arbitrary(code)';
     const transformOptions = {arbitrary: 'options'};
     transformCode(transformer, filename, sourceCode, {transform: transformOptions}, () => {});
-    expect(transformer.transform).toBeCalledWith(
-      sourceCode,
+    expect(transformer.transform).toBeCalledWith({
       filename,
-      transformOptions,
-    );
+      options: transformOptions,
+      src: sourceCode,
+    });
   });
 
   it('prefixes JSON files with an assignment to module.exports to make the code valid', function() {
     const filename = 'arbitrary/file.json';
     const sourceCode = '{"arbitrary":"property"}';
     transformCode(transformer, filename, sourceCode, {}, () => {});
-    expect(transformer.transform).toBeCalledWith(
-      `module.exports=${sourceCode}`,
+    expect(transformer.transform).toBeCalledWith({
       filename,
-      undefined,
-    );
+      options: undefined,
+      src: `module.exports=${sourceCode}`,
+    });
   });
 
   it('calls back with the result of the transform in the cache', done => {
diff --git a/packager/src/JSTransformer/worker/worker.js b/packager/src/JSTransformer/worker/worker.js
index c674a1bed..f1890c954 100644
--- a/packager/src/JSTransformer/worker/worker.js
+++ b/packager/src/JSTransformer/worker/worker.js
@@ -29,13 +29,13 @@ export type TransformedCode = {
 };
 
 export type Transformer<ExtraOptions: {} = {}> = {
-  transform: (
+  transform: ({|
     filename: string,
-    sourceCode: string,
     options: ExtraOptions & TransformOptions,
     plugins?: BabelPlugins,
-  ) => {ast: ?Ast, code: string, map: ?MappingsMap},
-  getCacheKey: TransformOptionsStrict => string,
+    src: string,
+  |}) => {ast: ?Ast, code: string, map: ?MappingsMap},
+  getCacheKey: () => string,
 };
 
 
@@ -102,7 +102,11 @@ function transformCode(
 
   let transformed;
   try {
-    transformed = transformer.transform(sourceCode, filename, options.transform);
+    transformed = transformer.transform({
+      filename,
+      options: options.transform,
+      src: sourceCode,
+    });
   } catch (error) {
     callback(error);
     return;
diff --git a/packager/src/ModuleGraph/worker/__tests__/transform-module-test.js b/packager/src/ModuleGraph/worker/__tests__/transform-module-test.js
index bb4af0f72..ef45c1738 100644
--- a/packager/src/ModuleGraph/worker/__tests__/transform-module-test.js
+++ b/packager/src/ModuleGraph/worker/__tests__/transform-module-test.js
@@ -95,10 +95,16 @@ describe('transforming JS modules:', () => {
       const variants = {dev: {dev: true}, prod: {dev: false}};
 
       transformModule(sourceCode, options(variants), () => {
-        expect(transformer.transform)
-          .toBeCalledWith(sourceCode, filename, {...defaults, ...variants.dev});
-        expect(transformer.transform)
-          .toBeCalledWith(sourceCode, filename, {...defaults, ...variants.prod});
+        expect(transformer.transform).toBeCalledWith({
+            filename,
+            options: {...defaults, ...variants.dev},
+            src: sourceCode,
+          });
+        expect(transformer.transform).toBeCalledWith({
+            filename,
+            options: {...defaults, ...variants.prod},
+            src: sourceCode,
+          });
         done();
       });
     },
diff --git a/packager/src/ModuleGraph/worker/transform-module.js b/packager/src/ModuleGraph/worker/transform-module.js
index 47dcd0a27..38e5a6007 100644
--- a/packager/src/ModuleGraph/worker/transform-module.js
+++ b/packager/src/ModuleGraph/worker/transform-module.js
@@ -70,11 +70,11 @@ function transformModule(
   const {filename, transformer, variants = defaultVariants} = options;
   const tasks = {};
   Object.keys(variants).forEach(name => {
-    tasks[name] = asyncify(() => transformer.transform(
-        code,
+    tasks[name] = asyncify(() => transformer.transform({
         filename,
-        {...defaultTransformOptions, ...variants[name]},
-      )
+        options: {...defaultTransformOptions, ...variants[name]},
+        src: code,
+      })
     );
   });
 
diff --git a/packager/transformer.js b/packager/transformer.js
index 55447ee43..1aefd50e6 100644
--- a/packager/transformer.js
+++ b/packager/transformer.js
@@ -112,11 +112,14 @@ function buildBabelConfig(filename, options) {
   return Object.assign({}, babelRC, config);
 }
 
-function transform(
-  src: string,
+type Params = {
   filename: string,
-  options,
-) {
+  options: TransformOptions,
+  plugins?: BabelPlugins,
+  src: string,
+};
+
+function transform({filename, options, src}: Params) {
   options = options || {};
 
   const OLD_BABEL_ENV = process.env.BABEL_ENV;
@@ -154,7 +157,7 @@ function transform(
   }
 }
 
-function getCacheKey(options: TransformOptions) {
+function getCacheKey() {
   var key = crypto.createHash('md5');
   cacheKeyParts.forEach(part => key.update(part));
   return key.digest('hex');